“The show’s back next season, but we don’t even know which cast members will actually be back,” Morrison tells the Washington Post at the April 28 White House Correspondents Dinner. “I think I’ll be back, but some of the kids — we’re trying to figure out what we’re going to do with that.”

Morrison clarifies that it’s true — not everyone will be back for Season 4. So that will make May 11, the last day of filming for Season 3, all the more poignant.

“They’re treating it very sensitively, because for a lot of these kids it will be their last show,” he says. “I’m really happy that they’re treating it with such sensitivity and making the stories so great to end the show for some of these people.”

Are you surprised that not everyone will be back? Which seniors do you hope return in the fall?